Recently, portable terminals are being widely used as useful articles of modern persons without distinction of age and sex, and service providers and terminal manufacturers are competitively developing products (and services) for differentiation from other competitors.
For example, portable terminals are evolving into multimedia devices to provide various services such as phone books, games, Short Message Service (SMS), electronic mail (e-mail), wake-up calls, MPEG-1 Audio Layer 3 (MP3), schedule managing functions, digital cameras, and wireless Internet services.
Recently, since it has been suggested that electromagnetic waves generated by portable terminals may affect human bodies, terminal manufacturers are considering a counterplan for controlling the absorption of electromagnetic waves by users.
For example, a portable terminal controls the strength of transmission (TX) power to reduce an electromagnetic wave absorptance.
When a human body accesses (approaches) a portable terminal, the portable terminal reduces the TX power to reduce the absorption of electromagnetic waves by the human body.
In order to perform the above operation, the portable terminal has a proximity sensor and uses a sensing value to determine whether the human body has approached the portable terminal.
In order to reduce the power consumption of a portable terminal, a proximity sensor may be used to determine whether the portable terminal is in a call state. This method also uses a proximity sensor to determine the approach of a human body to a portable terminal.
A portable terminal size decreases for portability. However, when a portable terminal has a proximity sensor, there may be a limit in reducing the size of the portable terminal.
Also, when a portable terminal has a proximity sensor, the unit production cost of the portable terminal increases.
What is therefore required is an apparatus and method for determining the approach of a human body in a portable terminal without using a proximity sensor.